This file is an exploratory analysis of the effect of climate-induced shifts in angler catch-per-trip of Gulf of Maine cod and haddock. Results are based on 100 iterations of the recreation demand model. The RDM is calibrated to 2020 fishery conditions.

Baseline (2020) fishery statistics

Index “_i” indicates per choice occasion variable

           variable     mean       sd
               draw     50.5  29.0115
    estimated_trips 312755.1   0.9653
 n_choice_occasions   483934 2193.714
      tot_cod_catch 588077.5 1903.489
       tot_keep_cod 5044.494  53.3831
        tot_rel_cod   583033 1897.925
     tot_hadd_catch  1918895  4220.46
      tot_keep_hadd  1004515 2038.446
       tot_rel_hadd 914379.9 2380.872
         cod_keep_i   0.0104    1e-04
        hadd_keep_i   2.0758   0.0091
      cod_keep_trip   0.0161    2e-04
     hadd_keep_trip   3.2118   0.0065
        cod_catch_i   1.2152   0.0067
       hadd_catch_i   3.9653    0.018
     cod_catch_trip   1.8803   0.0061
    hadd_catch_trip   6.1355   0.0135

Baseline welfare calculations

After calibrating the simulation model to 2020 fishery conditions, I re-ran the model under two closure scenarios: (a) bag limits for both cod and haddock set to zero, and (b) bag limits for cod only set to zero.
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Scenario (a): close both fisheries

CV per choice occasion

  mean   sd
 62.88 0.44

Aggregate CV

     mean       sd
 30461985 157733.2

Number of trips under closure

     mean     sd
 260020.2 549.17

Number of trips under baseline fishery

     mean   sd
 312754.9 1.01

Percent reduction in trips from baseline fishery

   mean   sd
 -16.86 0.18

Scenario (b): close cod only

CV per choice occasion

 mean   sd
 0.89 0.18

Aggregate CV

   mean      sd
 429052 85388.3

Number of trips under closure

     mean     sd
 312081.8 153.72

Number of trips under baseline fishery

     mean   sd
 312754.9 1.01

Percent reduction in trips from baseline fishery

  mean   sd
 -0.22 0.05

Historical projected fishery outcomes

Total CV

Difference in CV between ind. and corr (cv_sum_corr-cv_sum_ind)

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Annual fishery outcomes under climate-induced changes in catch-per-trip

Each tab contains projected fishery outcomes based on input data from alternative copula models. #### Changes catch outcomes and temperatures relative to 2020

Projected decadal CV as a proportion of CV under full-closure of 2020 fishery

Clayton (independent catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

Total CV and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Clayton (correlated catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

Total CV and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Gumbel (independent catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

Total CV and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Gumbel (correlated catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

Total CV and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Frank (independent catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

Total CV and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Frank (correlated catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

Total CV and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Plackett (independent catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

Total CV and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Plackett (correlated catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

Total CV and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Gaussian (independent catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

Total CV and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Gaussian (correlated catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

Total CV and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

All copulas (correlated catch, decade=1)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

Total CV and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

All copulas (correlated catch, decade=4)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

Total CV and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

All copulas (correlated catch, decade=8)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

Total CV and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

OLS meta-analaysis of simulation results

The following OLS regression uses as data the 10 sets of results above (5 copulas, each with independent and correlated catch).

OLS results of total monthly CV

OLS results of total monthly CV

Monthly fishery outcomes under climate-induced changes in catch-per-trip

For reference, here are the number of directed trips by mode and period (1st and 2nd half of month) in 2020.

MRIP point estimates of directed trips in 2020 by bi-monthly period

MRIP point estimates of directed trips in 2020 by bi-monthly period

Each tab below contains projected fishery outcomes at the monthly level based on input data from alternative copula models.

Clayton (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Clayton (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Gumbel (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Gumbel (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Frank (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Frank (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Plackett (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Plackett (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Gaussian (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

Gaussian (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

MC simulation #2a - annual fishery outcomes with alternative cod open seasons

In these simulations, I vary the cod open season across different months of the year.

The baseline (2020) open season for cod was Sep. 15-30 for private boat and September 7-October 8 for for-hire. Because the model time-step is bi-monthly (two periods per month: 1st half, 2nd half), I set the baseline private boat open season to the 2nd half of September and the baseline for-hire season to the 1st and 2nd half of September. Haddock was open all months in the baseline except March and the first half of April, when there was no directed trips.

I specified alternative cod open seasons by month for May, June, July, August, and October. To do this, I open the 2nd half of the month for private boat mode, and I open the 1st and 2nd half of the month for the for-hire mode.

In these simulations I use independent and correlated catch-per-trip data from the clayton copula model.

CV results below show the difference in total CV between cod open season of September and cod open season occurring an alternative month.

CV difference - Independent (decade=1)

CV difference - Independent (decade=5)

CV difference - Independent (decade=8)

CV difference - Correlated (decade=1)

CV difference - Correlated (decade=5)

CV difference - Correlated (decade=8)

Full results - Clayton (independent catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

Full results - Clayton (correlated catch)

Cod and haddock keep per choice occasion:

Cod and haddock catch per choice occasion:

CV per choice occasion and number of trips:

Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):

MC simulation #2b - monthly fishery outcomes with alternative cod open seasons

In these simulations, I vary the cod open season across different months of the year. The results here come from #2a above but are presented at the monthly level.

May open (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

June open (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

July open (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

August open (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

September open (baseline results) (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

October open (correlated catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

May open (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

June open (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

July open (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

August open (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

September open (baseline results) (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):

October open (independent catch)

Number of trips by month:

CV per choice occasion by month:

Cod keep per choice occasion by month:

Haddock keep per choice occasion by month:

Cod catch per choice occasion by month:

Haddock catch per choice occasion by month:

Correlation in keep of cod and haddock per choice occasion (kendall’s tau-b):

Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):